Ok, so sooner or later, you will get a message when you start up your pokemon game. It will read "The internal battery has run dry. The game can be played. However, clock-based events will no longer occur".

That will be annoying. Events such as the Lily Cove Department Store Clear Out sale, or the person that gives you a new berry each day, will never happen.

People will say that the "berry fix patch" will "fix" the problem. IT WILL NOT. The berry fix patch fixes a glitch in the game, it does not do anything to the battery.

So lets get started:

Things you will need
A Flathead Screwdriver ( a small one)
Needle-Nosed Pliers
Flat head Pliers
Soldering Iron
*Solder
Tweezers
(if you have a Tri-Wing screw driver thats small, you won't need a flathead screwdriver)
New battery: CR 16 16T 3V(volts)
Electrical tape or duct tape

Step1:
Start heating up your soldering iron now so you don't have to wait later on. Get your tri-wing or flat head screwdriver and begin to remove the screw on the back of the GBA cartidge.
[images are to big for this thread so click on the links]
http://famikom.comze.com/files/GBA-PO/IMG_0016.JPG
http://famikom.comze.com/files/GBA-PO/IMG_0019.JPG
http://famikom.comze.com/files/GBA-PO/IMG_0017.JPG

Step2:
Turn the GBA Cartridge to the front. Push the front plate/cover down and lift up.
[images are to big for this thread so click on the links]
http://famikom.comze.com/files/GBA-PO/IMG_0020.JPG
http://famikom.comze.com/files/GBA-PO/IMG_0021.JPG
http://famikom.comze.com/files/GBA-PO/IMG_0022.JPG

Step3:
Desolder the two circled points. They are the pins the connect to the battery.
[images are to big for this thread so click on the links]
http://famikom.comze.com/files/GBA-PO/IMG_0022.png
http://famikom.comze.com/files/GBA-PO/IMG_0024.JPG
http://famikom.comze.com/files/GBA-PO/IMG_0025.JPG
http://famikom.comze.com/files/GBA-PO/IMG_0026.JPG
http://famikom.comze.com/files/GBA-PO/IMG_0027.JPG

Step4:
You will notice that the bottom battery pin is glued to the battery! This poses a problem.. but no fear. Put your soldering iron on top of the metal pin glued to the battery. Keep it there for 30 seconds. Now using two pliers, "peel" it off. You may need to twist the metal pin because its on there pretty good. After that, use the flat head pliers to straighten out the pin if you twisted it.
[images are to big for this thread so click on the links]
http://famikom.comze.com/files/GBA-PO/IMG_0028.JPG
http://famikom.comze.com/files/GBA-PO/IMG_0029.JPG

Step5:
On the battery is a little protective ring. You will need that for your replacement battery. So carefully using tweezers take it off. If it doesn't come off as a whole or it is to hard to do so, make a small tare.
[images are to big for this thread so click on the links]
http://famikom.comze.com/files/GBA-PO/IMG_0030.JPG
http://famikom.comze.com/files/GBA-PO/IMG_0031.JPG

Step6:
Put the protective ring on the new battery. Take the bottom pin from Step4, and using small piece of electrical tape or duct tape ti tape it to the Positive side of the battery. Then solder the pin back on to the GBA circuit. Solder the top in back on as well. Tape this to the battery too. Put it in the cartridge close it up, and screw it closed. You now have successfully changed the battery! Enjoy!
Images were lost during this part! sorry guys!